libstage: add stage_[sg]et_position()

Starting to get an inkling of a need for a more hierarchical structure for
the stage.  Something which allows arbitrary grouping of nodes which can
then be moved around and even scaled as one at the parent.

2 files changed, 17 insertions, 0 deletions

diff --git a/src/stage.c b/src/stage.c
index c30f785..7871f8f 100644
--- a/src/stage.c
+++ b/src/stage.c
@@ -52,6 +52,7 @@ struct stage_t {
 	list_head_t	layers[STAGE_LAYERS_MAX];
 	SDL_Renderer	*renderer;		/* target renderer */
 	float		aspect_ratio;		/* width/height ratio of stage, -1.0...1.0 range of node coordinates map to this ratio. */
+	v2f_t		position;		/* position of the stage (defaults to 0,0) */
 	float		alpha;			/* alpha to apply to all nodes */
 };
 
@@ -339,6 +340,20 @@ void stage_get_alpha(stage_t *stage, float *res_alpha)
 }
 
 
+/* set the global position for the stage, all nodes are shifted by this @ render time */
+void stage_set_position(stage_t *stage, v2f_t *position)
+{
+	stage->position = *position;
+}
+
+
+/* get the global position for the stage */
+void stage_get_position(stage_t *stage, v2f_t *res_position)
+{
+	*res_position = stage->position;
+}
+
+
 static void aabb_to_rect(const aabb_t *aabb, const v2f_t *pos, const SDL_Rect *stage_rect, SDL_Rect *res_rect)
 {
 	float	half_w = ((float)stage_rect->w) * .5f, half_h = ((float)stage_rect->h) * .5f;	/* FIXME silly to recompute this repeatedly... */
diff --git a/src/stage.h b/src/stage.h
index d29a763..e16f917 100644
--- a/src/stage.h
+++ b/src/stage.h
@@ -36,6 +36,8 @@ stage_t * stage_free(stage_t *stage);
 void stage_fit(float aspect_ratio, int width, int height, int *res_width, int *res_height);
 void stage_set_alpha(stage_t *stage, float alpha);
 void stage_get_alpha(stage_t *stage, float *res_alpha);
+void stage_set_position(stage_t *stage, v2f_t *position);
+void stage_get_position(stage_t *stage, v2f_t *res_position);
 void stage_render(const stage_t *stage);
 stage_node_t * stage_node_new(stage_t *stage, int layer, const char *name, void *object, stage_render_func_t render_func, stage_free_func_t free_func);